1. Field of Invention
The invention relates to a testing jig and, in particular, to a circuit board testing jig, which assembles and aligns the circuit board easily.
2. Related Art
For maintaining the fabrication quality of a circuit board, an electrical test for the circuit board or components of the circuit board is usually performed after the circuit board is manufactured.
FIG. 1 is a schematic view showing a conventional circuit board testing equipment. The conventional circuit board testing equipment comprises a circuit board testing machine 1 and a circuit board testing jig 2 used in the circuit board testing machine 1.
Referring to FIG. 1, the circuit board testing jig 2 comprises a first testing unit 21, a second testing unit 22 and a carrier 23, wherein the first testing unit 21 is also called a bottom fixture and the second testing unit 22 is also called a top fixture.
The second testing unit 22 is connected with a pressure plate 11 of the circuit board testing machine 1. When the pressure plate 11 of the circuit board testing machine 1 presses downwardly, the second testing unit 22 is forced and moves along the direction of the applied force. Thus, the second testing unit 22, the carrier 23 and the first testing unit 21 are assembled, and a circuit board 3 positioned on the carrier 23 can be then tested.
Referring to FIG. 2, the first testing unit 21 includes a plurality of probes 211 and connectors 212. The probes 211 protrude from the first testing unit 21 and correspond to the pins of the electrical component 31 of the circuit board 3. Besides, the first testing unit 21 further includes at lease one first alignment hole 213, a plurality of elastic component 214 and at least one second alignment hole 215.
The second testing unit 22 is set above the first testing unit 21 and is composed of a plurality of rods 221, an alignment plate 222 and a detecting plate 223. The rods 221 are arranged between the alignment plate 222 and the detecting plate 223, so that the alignment plate 222 and the detecting plate 223 are parallel to one another. The alignment plate 222 is connected with the pressure plate 11. The detecting plate 223 includes at least one first alignment rod 224, a plurality of probes 225 corresponding to pins of the electrical component 31 of the circuit board 3 and a connector 226.
The carrier 23 is set between the first testing unit 21 and the second testing unit 22, and one side of the carrier 23 carriers the circuit board 3. The carrier 23 includes at least one carrier alignment hole 231 corresponding to the first alignment hole 213 of the first testing unit 21 and holes 233 corresponding to pins of the electrical component 31 of the circuit board 3. Besides, the opposite side of the carrier 23 includes at lease one second alignment rod 232.
Referring to FIGS. 1, 2 and 3, when testing the circuit board 3, firstly the second testing unit 22 is fixed to the pressure plate 11 of the circuit board testing machine 1. The first testing unit 21 is fixed on the platform 12 of the circuit board testing machine 1. Then, the circuit board 3 is positioned on the carrier 23.
The second alignment rod 232 of the carrier 23 is then inserted into the second alignment hole 215 of the first testing unit 21. In this case, the carrier alignment hole 231 is provided corresponding to the first alignment hole 213 of the first testing unit 21. After that, a control unit is used to control the action of the pressure plate 11, so that the first alignment rod 224 passes through the carrier alignment hole 231 and inserts into the first alignment hole 213 of the first testing unit 21. The probes 225 of the second testing unit 22 and the probes 211 of the first testing unit 21 are connected to pins of the electrical component 31 of the circuit board 3. Every connector of the circuit board testing jig 2 is electrically coupled to the circuit board testing machine 1, so as to use the circuit board testing machine 1 to test the electrical characters of the circuit board 3.
Referring to FIG. 4, owing to the diameter of the carrier alignment hole 231 is larger than the diameter of the first alignment hole 213 of the first testing unit 21, the first alignment rod 224 of the second testing unit 22 could not be facilely aligned to insert into the first alignment hole 213 after it passes through the carrier alignment hole 231. Accordingly, the operator should spend more time and be more careful to align the first alignment rods 224 and to make them pass through the carrier 23 and insert into the corresponding first alignment holes 213 of the first testing unit 21. In other words, the conventional circuit board testing jig has some drawbacks as described below:                1. Difficult alignment: It is hard to align every first alignment rod 224 of the second testing unit 22 and to directly insert it into the corresponding first alignment hole 213 of the first testing unit 21. Thus, the operator may spend more time to perform this testing process.        2. Jig is easily damaged: Referring to FIGS. 4 and 5, the pressure plate 11 of the circuit board testing machine 1 applies a force to the circuit board testing jig 2. If the first alignment rod 224 of the second testing unit 22 is not insert into the first alignment hole 213 of the first testing unit 21 and is against the first testing unit 21, the second testing unit 22 would be damaged when the pressure plate 11 moves toward the second testing unit 22. Since the first alignment rods 224 of the second testing unit 22 directly press the first testing unit 21, the second testing unit 22 made by acrylic or glass would be broken, resulting in the damage of the circuit board testing jig 2.        
It is therefore an important subjective of the invention to provide a circuit board testing jig that can solve the above-mentioned problems.